The lawsuit alleges Anthony made numerous misrepresentations to the group and its founder, Tim Miller.

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As a result, volunteers engaged in "extensive, costly and time-consuming searches for Caylee," the lawsuit claims. "The time and effort dedicated to this search diverted resources from TES' ability to provide its search and rescue operations to other families."

Texas EquuSearch said it did not know in the summer and fall of 2008 that Caylee died June 16, as her defense claimed in its opening statement at her first-degree murder trial.

The lawsuit claims the trial was the first time the organization learned of the claims of accidental death. It seeks damages in excess of $15,000.

Texas EquuSearch claims it spent more than $112,000 in the search for Caylee, the second most costly in the organization's history. The organization relies upon charitable donations to fund its searches. This search, it said, consumed 40 percent of the organization's annual budget. It said 4,200 volunteers helped search for Caylee.

"Casey Anthony never corrected or otherwise disagreed with any statements made by Cindy Anthony and George Anthony that Caylee was still alive," the lawsuit reads.

During the search for Caylee, the organization received more than 15 requests from other families seeking help in searching for a missing loved one.